1. RESPIRATORY SYSTEM

3. PARTS OF RESPIRATORY SYSTEM 1. Nose 2.Pharynx UPPER RESPIRTORY TRACT 3.Larynx 4.Trachea 5.Bronchial tree LOWER RESPIRTORY TRACT 6.Lungs

4. UPPER RESPIRATRY TRACT

5. THE NOSE Structure: It is formed by 2 nasal cavities separated from each other by nasal septum & separated from the mouth cavity by the palate. Communications: to the outside by the external nasal openings & to the nasopharynx by the internal nasal openings. Functions: 1.Air way passage. 2.Air warming (by its blood vessels). 3.Air moistening (by its mucus secretion). 4.Trapping of foreign particles. N.B.: The paranasal sinuses: They are cavities inside the bone of skulls. They lighten the skull.

6. THE PHARYNX Structure: It is a muscular tube. Function: It is a common pathway for air and food. Parts: Nasopharynx, oropharynx & laryngopharynx. Pharyngeal tonsils: Collection of lymphatic tissue in nasopharynx. Palatine tonsils: Collection of lymphatic tissue in oropharynx.

7. THE LARYNX 9 cartilages Structure: It is formed of 9 cartilages united by ligaments & muscles.  Thyroid cartilage  Thyroid cartilage: largest cartilage, forms “Adams apple” in male.  Epiglottis:  Epiglottis: closes superior opening of larynx when we are swallowing. Functions: 1.Pathway of air. 2.Production of voice by vocal cords.

8. THE TRACHEA Structure: A tube formed of C-shaped cartilage rings (Why C-shaped? To allow distention of esophagus). Site: It extends from the neck to thorax, in front of esophagus. Termination: It divides into 2 primary bronchi. Function: Pathway of air.

9. THE BRONCHIAL TREE right bronchus largerstraighter Right & left primary bronchi: right bronchus is larger and straighter than left : inhaled foreign object go mostly to right bronchus. Primary bronchi divides into smaller bronchi then to bronchioles. Function: Pathway of air

10. LUNG & ALVEOLI

11. THE LUNGS Site: They occupy all the thoracic cavity except for the central area where heart is found. Shape: They are conical in shape, with apex directed upward. 1.The right lung 1.The right lung is larger, shorter & has 3 lobes. 2.The left lung 2.The left lung is smaller, longer & has 2 lobes. Structure: They are formed of air spaces (alveoli) surrounded by elastic tissue. Function: area of gas exchange between blood & inspired air. prevents friction N.B.: The pleura: A double-layered sac that surrounds the lung. Between both layers there is a cavity filled with fluid. It prevents friction of lungs with thoracic cage.